Life events, important emotional losses, difficult life situations, and psychological characteristics were investigated in a case-control study of 87 breast cancer patients and their controls. In a second part, the effect of stressful life events preceding cancer diagnosis on survival was studied in an 8-year follow-up of the breast cancer group. The control group was selected from the general female population and matched for sex, age, number of child-births, and language. The findings showed that breast cancer patients had significantly more life events, important losses, and difficult life situations prior to the discovery of the breast tumor than controls. The analysis indicated that important losses during a 6-year prodromal period and life event scores prior to examination on both the 12-month and modified 6-year Social Readjustment Rating Scale were associated with subsequent development of breast cancer. The association persisted after adjustment for marital status, education, and social class. The findings of the survival analyses indicated that life events in the 12 months preceding the onset of breast cancer and lower social class were associated with a smaller chance of disease-free and overall survival after controlling for clinical factors.